I agree it's good for energy savings but for scrubber efficiency I disagree. Not trying to be a critic here, just pointing out a few facts, and a couple things to think about, not necessarily for only you but also for anyone else looking at this setup and thinking about doing a similar one
A 48x48 single-sided scrubber is big enough to handle almost 100 cubes of food per day if it were properly built. I would put yours at more like more like 40 cubes/day, knocked back because it's on glass, and because it's non-vertical, and because it doesn't get sunlight 18 hours/day. Since it's oversized (because I doubt you feed that much) the algae tries to spread out across a larger area and it doesn't grow as efficiently (bushy green being the best), plus the bare glass substrate doesn't allow it to form a very strong adhesion so you can't put enough flow across it or it will detach (35 GPH/in, and putting 1700 GPH over that I would surely think would cause detachment). I know from reading this thread that you started with a screen but it became too cumbersome to remove and I can only imagine trying to lift a 24x48 mat full of algae so I understand!!!
If there was a way to take the sunlight and redirect it so that you could utilize a vertical screen you could probably build one using the new feeding guideline which is 12 sq in of screen lit on both sides with a total of 12 watts total lighting, per cube of food per day. I'm guessing (can't remember if you posted how much you feed) that you're probably somewhere in the range of 10 cubes of food per day, which would be 120 sq in of screen with 60 watts of light on each side for 18 hours/day, or better yet, 120 watts per side and 9 hours/day. You would also have a screen that is more easily removed and cleaned remote from the tank. I recall you said that you trap the algae drippings with filter material and then have to run other filtration to take out the yellow tint, of course this is the major downfall of scrubbers in the past that did not have removable screens, and probably the #1 thing that people who have never run a scrubber before think about when knocking on them.
If you take the new feeding-based guidelines and apply them to your current setup, you would be able to use a smaller surface area and then you could use a screen again, if you were somehow able to focus the same amount of sunlight onto the smaller area. That would be able to handle more flow and you could reduce your reliance on other filtration needs to catch rouge algae and yellow water. Oh also yellow water, if you're getting that between cleanings, is a sign of the roots f the algae dying because they aren't getting enough light, which is also a downfall of under-lit and horizontal/slanted scrubbers.
However at this point that would probably be more effort than it's worth. I guess if it ain't broke, don't fix it, right?
Oh I just thought of another way to use the sun, and this might be worth considering. Why not use a bank of photocells to provide power to an LED array? You would still be using the sun to power it, but would be able to utilize a more efficient vertical screen system. Done right, you could run the LEDs much less than 18 hours a day, you could just pipe the power straight to the LEDs and whatever sunlight intensity you get would get translated (with some loss, of course) right over to the LED array. Just thinking out loud. No brain filter applied!